Glossary of Lasik Laser Eye Surgery Related Terms - Numbers-A

Fraction commonly used to indicate normal vision. A bottom number larger
than twenty indicates diminished vision. For example, a person with 20/400
vision would see a line of text that is twenty feet away with the same
readability that a person with "normal" vision would see that line of text
from 400 feet away.

Removal. In the case of the excimer laser, the frequency of energy causes
the molecules of the cornea to loose the "glue" that holds them together.
They simply fall away from each other and the remaining cornea.

The ability of the eye to change focus from distant objects to objects
closer than optical infinity, approximately 20 feet (6 meters). Like when
driving and you switch from looking down the road to reading the
speedometer. Accommodation is achieved when the lens shape is changed by
small muscles around the lens pushing and pulling. Loss of accommodation is
called Presbyopia.

Often called "lazy eye" it is a unilateral (occasionally bilateral)
condition in which, in the absence of any obvious structural anomalies or
ocular disease, the best corrected vision is less than 20/20 (6/6).
Amblyopia is often occurs in an eye that did not have adequate use during
early childhood.

Most often amblyopia results from either a misalignment of a child's eyes,
such as crossed eyes, or a difference in image quality between the two eyes
(one eye focusing better than the other.) In both cases, one eye becomes
stronger, suppressing the image of the other eye. If this condition
persists, the weaker eye may becomes useless.

With early diagnosis and treatment, the sight in the "lazy eye" can be
restored.

A medical specialty board that administers a 1-1/2 year long education and
examination process for ophthalmologists. After an ophthalmologist has
passed the examination, (s)he is "Board Certified". Click here to go to website.

Aniseikonia is a binocular condition in which left and right images differ
in size or shape. There are two types of aniseikonia – static and dynamic
aniseikonia. The first type is the classical aniseikonia, denoting a
perceived image size difference with a fixed gaze direction. Classic
aniseikonia can occur naturally or be induced by refractive surgery.

The second type of aniseikonia is also called induced anisophoria and
denotes a perceived image size difference due to unequal prism effects when
looking through different parts of the two (anisometropic) spectacle lenses. Detailed
Aniseikonia and Lasik Information

Also called Epithelium Basement Membrane Dystrophy, is a disease that
disrupts the ability of the epithelium to attach to the lower layers of the
cornea. The epithelium will often grow unevenly or will detach from the
cornea.

The absence of the eye's natural crystalline lens, usually after cataract
removal.

Aphakic Spectacles

Thick, plus-powered eyeglasses that were once the standard correction for
optical power following extraction of cataract. The glasses were cumbersome
and greatly distorted peripheral vision. Today, an intraocular lens (IOL) is
implanted in the eye after the cataract is removed.

A condition in which the surface of the cornea is not spherical, but is
irregularly shaped like the back of a spoon. An astigmatic cornea causes
light images to focus on two separate points in the eye, creating a
distorted image. Symptoms range from visual discomfort in mild cases, to
severe blurring, ghosting, and distortion similar to a reflection in a
fun-house mirror. The amount of astigmatism you have will appear in the
second number of most glasses prescriptions. The angle of direction
(cylinder meridian or axis) of the astigmatism will be shown in degrees. A
prescription of -4.00-1.00x30°, would indicate that you have 1.00 diopter of
astigmatism at 30 degrees axis.

A type of inherited allergic response involving elevated immunoglobulin E.
Sometimes called a reagin response, it means that you have hay fever,
bronchial asthma, or skin problems like urticaria or eczema. It can also be
acquired, sometimes following hepatitis or extended contact with solvents or
alcohol.

An incisional refractive surgery technique for low to moderate myopia (nearsighted, shortsighted vision). In the procedure, the
refractive surgeon places an instrument called an automated microkeratome on the eye which removes, in a shaving motion, a thin
layer of cornea only microns thick. An even thinner layer of cornea underneath this top cap is removed,
and the top cap is replaced. The procedure does not require sutures.

A computer-driven device used to plot defects in the visual field. Usually
the patient's head is placed into this large hemisphere shell. Various
points of lights, sometimes of different sizes, intensities, and colors are
projected onto the screen. The patient then indicates whether the light is
seen and the response is recorded. The computer then plots the effective
visual thresholds within the targeted visual field.